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problem-1-a-three-phase-four-pole-100-hp-induction-motor-is-rated-for-480-277-y-rms-at-60-hz-pa338
(Solved): Problem 1: A three-phase, four-pole, 100-hp induction motor is rated for (480)/(277)Y_(rms) at 60 Hz ...
Problem 1: A three-phase, four-pole,
100-hpinduction motor is rated for
(480)/(277)Y_(rms)at 60 Hz . The motor has the following constants per phase referred to the stator:
R_(s)=0.100\Omega ,R_(r)^(')=0.079\Omega ,x_(s)=
0.205\Omega ,x_(r)^(')=0.186\Omega , and
x_(m)=7.15\Omega . The total rotational losses incurred are 2950 W and are assumed to be constant. The core loss has been lumped in with the rotational losses. For a rotor slip of
3.333%at the rated voltage and frequency, determine the following quantities: a) the rotor speed,
n_(m);b) the power factor at which the motor operates,
PF_(motor );c) the developed output power,
P_(shaft );d) the developed output torque,
T_(shaft ); and e) the efficiency of the motor,
\eta _(motor ). Ans: a)
n_(m)=1740rpm; b)
PF_(motor )=0.898lagging; c)
P_(shaft )=77.113 kW ; d)
T_(shaft )=423.203N*m; e)
\eta _(motor )=88.753%.
